Automatic hang-off for reciprocating rod



March 13, 1962 J, AR 3,024,667

AUTOMATIC HANG-OFF FOR RECIPROCATING ROD Filed April 25, 1959 2 Sheets-Sheet 1 INVENTOR. J. F. HART ATTORNEY Q uzwmd, Q4

i March 13, 1962 J. F. HART 3,024,667 AUTOMATIC HANG-OFF FOR RECIPROCATING ROD Filed April 25, 1959 2 Sheets-Sheet 2 I INVENTOR.

J. F. HART wm iwm, m7?

ATTORNEY States Unite This invention is an automatic hang-oflf device. It is designed to disengage a reciprocating power transmission rod after a selected number of strokes by removing the tension which, in normal operation, serves to link the rod to the power source. The device is of particular utility in well pumping operations where it is frequently necessary to hook off or disconnect the pump from the power source permitting the well to regain a desired fluid level or, in some instances, to control the amount of fluid pumped from the well over a given period of time.

In many present operations the hanging on and oif of power to individual wells is accomplished manually by an attendant. This invention will automatically hang-off the well after a desired number of strokes have occurred. This relieves the attendant from having to be at the location when the well is to be taken off. Since the operation of the automatic hang-off is controlled entirely by the number of strokes, any loss of power or shut-down time has no effect on the total number of pump strokes before the automatic hang-off operates. Also, if the power is off when the attendant returns, a close indication of the percent pump strokes unused is shown.

The object of this invention is to provide a simple, reliable, automatic device for hanging off or disconnecting a power transmission rod. Further, the counting and control mechanism used in the invention is of very simple construction and can be contained in a housing to exploit its portability. The device requires at most very little adaptation of a conventional power transmission rod line and can easily be moved from one transmission rod line to another. Also, the automatic hook-off device of this invention may be located at any convenient distance from either the power source or the load.

As will be seen from the drawings a more or less conventional rod line can be adapted for automatic hook-off by providing a stop adjacent the rod line and in fixed relationship to the power source and load. The drawings show a rod line support used for this purpose for the sake of convenience, but any other fixed, that is, nonreciprocating, member can be used or placed adjacent the rod line. The rod line itself is provided with a projection between the coupling means and the stop and a projection between the stop and the pump load. The projection on the power or coupling side is so arranged that on the power stroke a distance is left between the projection and the support that is larger than the knockoff block and on the return stroke is smaller than the knock-off block. The projection on the load side of the stop is positioned Where it will strike a counter mechanism lever on the power stroke. Once the rod line is adapted in this way, the counting and control device of this invention may merely be placed in the proper relationship to the support and projections and set to operate after a predetermined number of strokes.

The counting and control mechanism of this invention, besides its desirable feature of portability uses a double retractible means for keeping the knock-off block suspended away from the rod line and for insuring that when the knock-off block falls, it will be after the desired number of reciprocations of the transmission line and at a phase in the reciprocation of the line when the projection between the coupling and the stop will be out of the way of the block, so that the block will fall squarely on the rod line and be caught between the projection and the stop in the next phase of the same reciprocation cycle. The double means comprises one means suspending the block until a predetermined number of strokes have been made by the rod line, and another means which is retracted from elfecting suspension at the phase of the cycle where the projection is a suflicient distance from the stop to permit the knock-off block to fall onto the rod line.

The features of the invention will be more readily understood from the following description in connection with the accompanying drawings in which:

FIGURE 1 is a sectional top view embodying the main features of the invention;

FIGURE 2 is a sectionalized side view of the invention through the line 2 of FIGURE 1; and

FIGURE 3 is a sectional end view showing details of the ratchet wheel.

Referring now to the drawings, 1 and 2 constitute rods in a rod line for transmitting power from a reciprocating power source, not shown, connected to rod 1, to a work load (not shown) connected to rod 2. The work load, in the drawings, exerts a force to the left. The force may be due, for example, to the weight of a reciprocating pump suspended in an oil well. The work load exerts sufficient force to the left to keep the linkage of eye 3, and hook 4, intact. Rod line 2 is in proximity to a stop. In the drawings the line extends through an opening, for example, the sleeve 3! in support 5 where the support functions also as the stop. These elements are conventional elements in a well pumping rod line. The automatic hang-off device is positioned so that knock-01f block 7, overhangs the section of rod line 2 which is between the stop 5 and the power side projection 6. In the drawings the rod line moves to the right on the power stroke and to the left on the return stroke. Knock-off block 7, is big enough to clog sleeve 30 in support 5 when it is in position 7'. Power side projection 6, and load side projection 8, are shown in the drawings as clamps or fasteners. These are the preferred type of projection, since they can be put on an existing rod line quickly and easily. However, fixed projections may be provided at positions 6 and 8 on the rod line 2 as, for example, by welding or otherwise fixedly connecting flanges or crossbars at these points to provide a block-hitting projection 6, and a lever-hitting projection 8. Block 7 is supported against gravity by a member which provides two seatsone for a means which is unseated on each reciprocation cycle, and one for a means which is unseated after the desired number of reciprocations. This may conveniently be the cross-member 44, which is illustrated and which pivots around the fulcrum 15.

The automatic actuating mechanism for the block 7, is contained in the box 32, which may be supported by legs 34, and/or the support 5 and transported by means of the handle 56. The control-counting device comprises, basically, a sensing means which is responsive to each reciprocation cycle of the rod line and which retracts one of the block-keepers on each cycle and which records the number of cycles performed in order to retract the other block-keeper when the desired number of cycles is completed. In the preferred embodiment illustrated the sensing means is the lever 9, which extends through a slot 36, in the bottom of the box 32, and which is attached to the box through pivot 10. In the event of overstroke of the rod line 2, a friction break point 24, may be provided on lever 9 to shear, preventing damage to the automatic disconnect mechamsm.

The counting mechanism comprises the bar 16, pivot lever assembly 18, pin 38, ratchet pawl 19, ratchet wheel 17, cam 20, threaded shaft 21, and movable bead 22.

Lever 9 actuates the counting mechanism through a connection at its upper end to the bar 16, which in turn is connected to pivot lever assembly 18. This assembly pivots around pin 38 which fastens it to the box 32, by means of tongue 40. Assembly 18 is biased to the right at one end by spring 25 and is attached at the other end to ratchet pawl 19. Cam 20, controls the amount of rotation of ratchet wheel 17. For example, by moving the cam 20 radially inwardly, the movement of pawl 19 along the teeth of ratchet wheel 17 is restricted so that the wheel moves less on each cycle. Circular movement of the wheel brings about rotation of the threaded shaft 21, which is fixedly attached to ratchet wheel 17, and extends through the box 32, being seated on end bearings 48. An internally threaded movable head is provided on this shaft. The bead is prevented from rotating with the shaft, and thus moves gradually toward the end of the box 32, remote from the cross-member 44 and the knock-off block 7 upon repeated movements of the lever 9 and rotation of wheel 17. The movable bead may be, for example the split nut 22, which can be easily moved to any starting position, and which can be kept from rotation by the track 50 which slidingly engages the split nut. Arm 23, is biased by spring 27, towards projecting from box 32 and is provided with a head 52, and extends through the box, seating on cross-member 44, at 54. The head 52, as can be seen from FIGURE 1, overhangs the path of the movable head or nut 22. As bead 22 contacts and moves head 52, arm 23 is drawn leftward off the seat 54 of member 44.

Lever 9 also bears the pin 11, which engages the slotted end 12, of shuttle 13, which slidingly extends through a sleeve in support 42, outside the box to the cross-member 44, of block-support 14. Shuttle 13, is biased by the spring 26 and is of such length that each rightward movement of the rod line 2, projection 8, and the bottom of lever 9, on the power stroke, cause movement of the shuttle 13, leftward off the seat 46, of member 44.

The device works as follows:

To initiate operation, split nut 22 is positioned towards the end of shaft 21 away from ratchet wheel 17, and control cam 20 is adjusted to allow pawl 19, to engage the number of teeth necessary to advance split nut 22 to engagement with head 52, after the selected number of pump strokes. On each power stroke left projection 8 moves lever 9, causing rotation of shaft 21 and movement of split nut 22, toward the ratchet wheel end of shaft 21 and track 50. When the split nut 22 strikes head 52, it moves arm 23 to the left, unseating the arm from the cross member 44. Pin 11, on lever 9, is located in slotted end 12 of shuttle 13, so that the shuttle is unseated from member 44, on each cycle as rod line 2 approaches the end of the power stroke. Therefore, at the end of the power stroke after the unseating of arm 23, cross-member 44, of the block support 14, is free to pivot around fulcrum 15, allowing block 7 to fall on rod line 2. Subsequent movement of rod line 2 to the left on the return stroke causes the clamp or other projection 6, to hit the block, now at position 7 preventing further leftward movement of rod line 2. With the tension on the line removed hook 4 is free to move in eye 3. The hook, unseated from the eye by gravity, will thus disengage and fall to the ground.

From the above description it can be seen that this automatic knock-off device is adaptable for many reciprocating transmission devices, particularly a reciprocating pump line, operating to disengage the power source after a selected number of strokes. It is understood that the drawings and description are illustrative only, and various modifications and changes can be made without departing from the spirit of the invention.

I claim:

1. A counting and control device for use in combination with a reciprocating power transmission rod line having a coupling between the power source and the load which is held together by tension due to the load, having a stop between the coupling and the load and being provided with a first projection between the stop and the load and with a second projection between the coupling and the stop, said control device comprising sensing means and a knock-off block, said block being adapted to be caught between the stop and the said second projection when said block rests on said rod line, thereby breaking the tension between power source and load, said knock-off block having suspension means and being held against the force of gravity away from said rod line by a shuttle and an arm which seat on the suspension means, said sensing means being adapted to move in response to the movement of said first projection on each reciprocation of the rod line, means for unseating said shuttle responsive to movement of the sensing means, and means for unseating said arm responsive to a predetermined number of movements of the sensing means.

2. A counting and control device for use in combination with a reciprocating power transmission rod line having a coupling between the power source and the load which is held together by tension due to the load, having a stop between the coupling and the load and being provided with a first projection between the stop and the load and with a second projection between the coupling and the stop, said control device comprising sensing means and a knock-off block, said block being adapted to be caught between the stop and the said second projection when said block rests on said rod line, thereby breaking the tension between power source and load, said knockoff block having suspension means and being held against the force of gravity away from said rod line by a shuttle and an arm which seat on the suspension means, said sensing means being adapted to move in response to the movement of said first projection on each reciprocation of the rod line, means for unseating said shuttle responsive to movement of the sensing means, and means for unseating said arm comprising a rotatable threaded shaft carrying a movable internally threaded head which is prevented from rotation with the shaft, means responsive to movement of the sensing means for rotating said shaft and a head attached to said arm adapted to be engaged by said movable head to move the arm in a direction remote from said suspension means to unseat said arm responsive to a predetermined number of movements of the sensing means.

3. The apparatus of claim 1 in which the suspension means is a cross-member pivotally connected with the block.

4. The apparatus of claim 1 in which the stop is a support for the rod line.

5. A counting and control device for use in combination with a reciprocating power transmission rod line having a coupling between the power source and the load which is held together by tension due to the load, having a support between the coupling and the load and being provided with a first projection between the support and the load and with a second projection between the coupling and the support, said control device comprising a sensing means and a knock-off block, said block being adapted to be caught between the support and the said second projection when said block rests on said rod line, thereby breaking the tension between power source and load, said knock-off block having suspension means comprising a cross-member pivotally connected with the block and being held against the force of gravity away from said rod line by a shuttle and an arm which seat on the cross-member, said sensing means being adapted to move in response to the movement of said first projection on each reciprocation of the rod line, means for unseating said shuttle responsive to movement of the sensing means, and means for unseating said arm comprising a rotatable threaded shaft carrying a moveable internally threaded bead which is prevented from rotation with the shaft, means responsive to movement of the sensing means for rotating said shaft and a head attached to said arm adapted to be engaged by said moveable bead to move the arm in a direction remote from said cross-member.

6. Apparatus comprising a reciprocating power transmission rod line having a coupling between the power source and the load which is held together by tension due to the load, having a stop between the coupling and the load and being provided with a first projection between the stop and the load and with a second projection between the coupling and the stop, in combination with a counting and control device which comprises a sensing means and a knock-off block, said block being adapted to be caught between the stop and the said second projection when said block rests on said rod line, thereby breaking the tension between the power source and load, said knock-off block having suspension means and being held against the force of gravity away form said rod line by a shuttle and an arm which seat on the suspension means, said sensing means being adapted to move in response to the movement of said first projection on each reciprocation of the rod line, means for unseating said shuttle responsive to movement of the sensing means, and means for unseating said arm responsive to a predetermined number of movements of the sensing means.

7. Apparatus comprising a reciprocating power transmission rod line having a coupling between the power source and the load which is held together by tension due to the load, having a stop between the coupling and the load and being provided with a first projection between the stop and the load and with a second projection between the coupling and the stop, in combination with a counting and control device which comprises a sensing means and a knock-oflf block, said block being adapted to be caught between the stop and the said second projection when said block rests on said rod line, thereby breaking the tension between the power source and load, said knock-off block having suspension means and being held against the force of gravity away from said rod line by a shuttle and an arm which seat on the suspension means, said sensing means being adapted to move in response to the movement of said first projection on each reciprocation of the rod line, means for unseating said shuttle responsive to movement of the sensing means, and means for unseating said arm comprising a rotatable threaded shaft carrying a movable internally threaded head which is prevented from rotation with the shaft, means responsive to movement of the sensing means for rotating said shaft, and a head attached to said arm adapted to be engaged by said movable head to move the arm in a direction remote from said suspension means to unseat said arm responsive to a predetermined number of movements of the sensing means.

8. The apparatus of claim 6 in which the suspension fieafis is a cross-member pivotally connected with the 9. The apparatus of claim 6 in which the stop is a support for the rod line.

10. Apparatus comprising a reciprocating power transmission rod line having a coupling between the power source and the load which is held together by tension due to the load, having 'a support between the coupling and the load and being provided with a first projection between the support and the load and with a second projection between the coupling and the support, in combination with a counting and control device which comprises a sensing means and a knock-01f block, said block being adapted to be caught between the support and the said second projection when said block rests on said rod line,

thereby breaking the tension between power source and load, said knock-01f block having suspension means comprising a cross-member pivotally connected with the block and being held against the force of gravity away from said rod line by a shuttle and an arm which seat on the cross-member, said sensing means being adapted to move in response to the movement of said first projection on each reciprocation of the rod line, means for unseating said shuttle responsive to movement of the sensing means, and means for unseating said arm comprising a rotatable threaded shaft carrying a moveable internally threaded bead which is prevented from rotation with the shaft, means responsive to movement of the sensing means for rotating said shaft and a head attached to said arm adapted to be engaged by said moveable bead to move the arm in a direction remote from said cross-member.

11. A counting and control device for use in combination with a reciprocating power transmission rod having a coupling between the power source and the load which is held together by tension due to the load, having a first, fixed, stop between the coupling and the load and being provided with an actuation means between the stop and the load and with a second, reciprocating, stop between the coupling and said first stop, said control device comprising a sensing means, a knock-off block adapted to be caught "between said stops when the block rests on said rod line, first and second holding means cooperating to hold said knock-0E block out of position between said stops, said sensing means adapted to be actuated by said actuation means upon reciprocation of the rod line, said sensing means upon actuation serving to release said first holding means when the distance between said stops is sufficient to accommodate the knock-elf block, and means for releasing said second holding means in response to a predetermined number of rod reciprocations, the release of said first and second holding means permitting the knock-off block to be caught between said stops thereby breaking the tension between power source and load and releasing said coupling.

12. Apparatus comprising a reciprocating power transmission rod line having a coupling between the power source and the load which is held together by tension due to the load, having a first, fixed, stop between the coupling and the load and being provided with an actuation means between the stop and the load and with a second, reciprocating, stop between the coupling and said first stop, in combination with a counting and control device which comprises a sensing means, a knock-off block adapted to be caught between said stops when the block rests on said rod line, first and second holding means cooperating to hold said knock-oft block out of position between said stops, said sensing means adapted to be actuated by said actuation means upon reicprocation of the rod line, said sensing means upon actuation serving to release said first holding means when the distance between said stops is suflicient to accommodate the knockoff block, and means for releasing said second holding means in response to a predetermined number of rod reciprocations, the release of said first and second holding means permitting the knock-oil? block to be caught between said stops thereby breaking the tension between power source and load and releasing said coupling.

References Cited in the file of this patent UNITED STATES PATENTS 2,320,051 Robinson May 25, 1943 2,334,943 Miller et al Nov. 23, 1943 2,633,801 Clements Apr. 7, 1953 

